wilfredguerin
Aerospace
- Sep 22, 2007
- 2
Please advise on the required design characteristics to facilitate COMMONER construction of footings and foundation to hold large (heavy) spheres.
This project is instigating the creation of large cement-hulled spheres to use for image target calibration for community mapping and 3d extrapolation. The design characteristics are simple, the best permanent materials and construction technique that is capable of withstanding environmental hazards (weather, baseball bats, vehicular impact, tampering) while still being easy for an average high school class to construct. The technical requirement is to be mounted to a fixed position with at least 10-year guaranteed location, preferably 100+ year in compatible natural environments.
Though the hull thickness of the sphere is roughly based on the difference between the next smaller nested size for production efficiency, there is need to formalize techniques for using standard (retail available) materials with economics in mind. (bar/etc)
The primary concern is this:
Even with a large cement shelled ball mounted to a common fence pole pipe or other mechanisms, anywhere from 6 inch or .2m diameter upwards through a 5 meter "BigBall" which is defined as a 1000-year permanence hull with predictable location and excessively over-engineered steel core and huge foundation, the specific foundation design for easy implementation and standardization must be determined.
My concern is the range between 1 foot upward to 3-4 meter diameter spheres; they are huge, heavy, structurally problematic (minimalist stem/mounting) and require a foundation that minimizes need for permits and cost while maximizing fixed characteristics and safety.
These are effectively lawn ornaments, a 1 yard diameter US standard is expected to be most popular. The 1 meter diameter counterpart is likely most common. The expected weight based on common quick-set cement mix with a minimalist hull is approximately 1200 pounds for a 1m shell plus bar / structural weight. This is based on a hull dimension the difference of 1m to 1 yard, does not yet have a spec for structural elements, and is expected to mount on a fence pole to conventional foundation that is easily and safely built by a common individual with no specific background.
A minimalist yardball with a questionably thin hull (inch) supported by various mesh/rod structures will weigh in at 560 pounds concrete and additional weight mounting/internal structure.
This would be expected to stand at least 1 foot above the surface with a minimal extruding pilon design to compensate for weather conditions and visibility, preferably with a minimal pipe/etc structure for mounting.
I appologise for being verbose, but this example needs standardization before we tell creative school kids to make huge spheres out of cheap cement and mount them in high, visible locations (like the top of the hill) without a very explicit foundation design that they can implement safely.
You understand the concern, even a 5cm thick hull will bounce around between trucks on the highway for quite a while crushing cars before it is ejected...
Please inform on a suitable design that would be scalable for these implementations and concentrated on .5m (480lb), .75m (400+lb), yard/meter (560-1200+?1680?lb), through larger sizes and viable for any terrain material or environment. Multiple 1 foot spheres (50+lb each) would likely also be mounted to structures rigidly in clusters of 3+...
I express the obvious concern with permanent mounting techniques, especially when in proximity to vehicles, shifty terrain, and, of course, other creative humans.
The goal is a 10+ year fixed position of each sphere with predictable movement at 100+ year ranges.
Thank you all in advance for your commentaries and technical response
-Wilfred
This project is instigating the creation of large cement-hulled spheres to use for image target calibration for community mapping and 3d extrapolation. The design characteristics are simple, the best permanent materials and construction technique that is capable of withstanding environmental hazards (weather, baseball bats, vehicular impact, tampering) while still being easy for an average high school class to construct. The technical requirement is to be mounted to a fixed position with at least 10-year guaranteed location, preferably 100+ year in compatible natural environments.
Though the hull thickness of the sphere is roughly based on the difference between the next smaller nested size for production efficiency, there is need to formalize techniques for using standard (retail available) materials with economics in mind. (bar/etc)
The primary concern is this:
Even with a large cement shelled ball mounted to a common fence pole pipe or other mechanisms, anywhere from 6 inch or .2m diameter upwards through a 5 meter "BigBall" which is defined as a 1000-year permanence hull with predictable location and excessively over-engineered steel core and huge foundation, the specific foundation design for easy implementation and standardization must be determined.
My concern is the range between 1 foot upward to 3-4 meter diameter spheres; they are huge, heavy, structurally problematic (minimalist stem/mounting) and require a foundation that minimizes need for permits and cost while maximizing fixed characteristics and safety.
These are effectively lawn ornaments, a 1 yard diameter US standard is expected to be most popular. The 1 meter diameter counterpart is likely most common. The expected weight based on common quick-set cement mix with a minimalist hull is approximately 1200 pounds for a 1m shell plus bar / structural weight. This is based on a hull dimension the difference of 1m to 1 yard, does not yet have a spec for structural elements, and is expected to mount on a fence pole to conventional foundation that is easily and safely built by a common individual with no specific background.
A minimalist yardball with a questionably thin hull (inch) supported by various mesh/rod structures will weigh in at 560 pounds concrete and additional weight mounting/internal structure.
This would be expected to stand at least 1 foot above the surface with a minimal extruding pilon design to compensate for weather conditions and visibility, preferably with a minimal pipe/etc structure for mounting.
I appologise for being verbose, but this example needs standardization before we tell creative school kids to make huge spheres out of cheap cement and mount them in high, visible locations (like the top of the hill) without a very explicit foundation design that they can implement safely.
You understand the concern, even a 5cm thick hull will bounce around between trucks on the highway for quite a while crushing cars before it is ejected...
Please inform on a suitable design that would be scalable for these implementations and concentrated on .5m (480lb), .75m (400+lb), yard/meter (560-1200+?1680?lb), through larger sizes and viable for any terrain material or environment. Multiple 1 foot spheres (50+lb each) would likely also be mounted to structures rigidly in clusters of 3+...
I express the obvious concern with permanent mounting techniques, especially when in proximity to vehicles, shifty terrain, and, of course, other creative humans.
The goal is a 10+ year fixed position of each sphere with predictable movement at 100+ year ranges.
Thank you all in advance for your commentaries and technical response
-Wilfred
